Multiple-dimension imaging sensor with operation based on detection of placement in mouth

ABSTRACT

Methods and systems are described for operating an intra-oral imaging sensor that includes a housing, an image sensing component at least partially housed within the housing, and a temperature sensor. An output of the temperature indicative of a sensed temperature is received and evaluated to determine whether the intra-oral imaging sensor is positioned in the mouth of the patient. The determination of whether the temperature sensor may be based on one or more determined conditions including whether a current temperature exceeds a threshold, whether a first derivative of the sensed temperature exceeds a rate-of-change threshold, and whether a second derivative of the sensed temperature exceeds a temperature acceleration threshold. In some implementations, the operation of the intra-oral imaging sensor is automatically adjusted in response to a determination that the sensor has been placed inside the mouth of a patient.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/627,199, filed Jun. 19, 2017, entitled “MULTIPLE-DIMENSION IMAGINGSENSOR WITH OPERATION BASED ON MAGNETIC FIELD DETECTION,” which is acontinuation-in-part of U.S. application Ser. No. 15/265,753, filed Sep.14, 2016, entitled “MULTIPLE-DIMENSION IMAGING SENSOR AND STATE-BASEDOPERATION OF AN IMAGING SYSTEM INCLUDING A MULTIPLE-DIMENSION IMAGINGSENSOR,” the entire contents of both of which are incorporated herein byreference.

BACKGROUND

Embodiments relate to systems and methods for capturing images using asensor.

X-ray imaging systems often include a sensor for detecting x-rayradiation that has passed through an object of interest or structure.For example, in dental applications, an intra-oral sensor may bepositioned in the mouth of a patient. X-ray radiation is directed at theobject of interest and toward the sensor. Data output from theintra-oral sensor is processed to generate an x-ray image of the objectof interest, for example, one or more teeth or other dental structures.

SUMMARY

In some instances, a multi-dimensional sensor is incorporated into anintra-oral x-ray sensor (sometimes referred to as an “imaging sensor”).The multi-dimensional sensor can include, for example, athree-dimensional accelerometer, a three-dimensional gyroscopic sensor,and a three-dimensional magnetometer to provide nine-dimensions ofpositional and movement information for the imaging sensor. In someinstances, additional or alternative sensors may also be incorporatedinto the imaging sensor including, for example, a temperature sensor, acurrent/voltage sensor or monitoring circuit, and an air pressuresensor.

Among other things, an imaging sensor equipped with a multi-dimensionalsensor can be used to determine when the imaging sensor is properlyaligned with an x-ray source and with a dental structure to be imaged.In addition, information provided by the multi-dimensional sensor can beused by an imaging system to determine when to arm the imaging sensor,to determine the “health” of the imaging sensors, and, in someimplementations, when to place the imaging sensor in a “low power” mode.

In one embodiment, the invention provides a method for operating animaging sensor, the imaging sensor including a multi-dimensional sensor.An electronic processor receives an output from the multi-dimensionalsensor and transitions the imaging sensor from a first operating stateinto a second operating state in response to a determination by theelectronic processor, based on the output from the multi-dimensionalsensor, that a first state transition criteria is satisfied.

In another embodiment, the invention provides a method for operating animaging sensor, the imaging sensor including a multi-dimensional sensor.An electronic processor operates the imaging sensor in a low-powerstate. In some embodiments, while operating in the low-power state, theimaging sensor does not capture any image data and is not able totransition directly into an “armed” state in which image data iscaptured. The electronic processor receives an output from themulti-dimensional sensor and transitions the imaging sensor from thelow-power state into a ready state in response to a determination by theelectronic processor, based on the output from the multi-dimensionalsensor, that a first state transition criteria is satisfied. Theelectronic processor also transitions the imaging sensor from the readystate into an armed state in response to a determination made by theelectronic processor, based on the output from the multi-dimensionalsensor, that a second state transition criteria is satisfied. Theelectronic processor operates the imaging sensor to capture image dataonly when operating in the armed state and does not transition from thelow-power state directly into the armed state based on automated statetransition criteria from the multi-dimensional sensor.

In yet another embodiment, the invention provides an imaging system thatincludes an intra-oral imaging sensor and an electronic processor. Theintra-oral imaging sensor includes a housing, an image sensing componentat least partially housed within the housing, and a magnetometer atleast partially housed within the housing. The electronic processor isconfigured to receive an output of the magnetometer indicative of anactual magnetic field that impinges the intra-oral imaging sensor. Theelectronic processor compares the data indicative of the actual magneticfield based on the output of the magnetometer to data indicative of afirst expected magnetic field. In response to determining, based on thecomparison, that the actual magnetic field matches the first expectedmagnetic field, the electronic processor alters the operation of theimaging system. In some embodiments, the electronic processor causes theintra-oral imaging sensor to operate in a low-power state in response todetermining that the actual magnetic field matches a first expectedmagnetic field indicative of placement of the intra-oral imaging sensorin an imaging sensor storage compartment.

In some embodiments, the invention provides an imaging system thatincludes an intra-oral imaging sensor and an electronic processor. Theintra-oral imaging sensor includes a housing, an image sensing componentat least partially housed within the housing, and a multi-dimensionalsensor at least partially housed within the housing. The electronicprocessor is configured to receive an output of the multi-dimensionalsensor indicative of movement of the intra-oral imaging sensor. Theoutput is compared to predetermined movement criteria indicative of atype of movement and, in response to determining that the type ofmovement of the imaging sensor has occurred, the electronic processoralters the operation of the imaging system.

In still other embodiments, the invention provides an imaging systemthat includes an intra-oral imaging sensor, an image sensing component,a multi-dimensional sensor, and an electronic processor. The intra-oralimaging sensor includes a housing and the image sensor component and themulti-dimensional sensor are at least partially housed within thehousing. The multi-dimensional sensor includes a three-dimensionalaccelerometer, a three-dimensional gyroscope, and a three-dimensionalmagnetometer. The electronic processor is configured to execute one ormore error condition check routines to determine whether an errorcondition is present based on an output received from themulti-dimensional sensor.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram of an imaging system including amulti-dimensional sensor integrated into the imaging sensor housingaccording to one embodiment.

FIG. 1B is a block diagram of an imaging sensor for use in the imagingsystem of FIG. 1A with a three-controller logic architecture.

FIG. 2A is a flowchart of method for checking a sensor for errorsperformed by the imaging system of FIG. 1A.

FIG. 2B is a flowchart of a method for checking the sensor voltage inthe method of FIG. 2A.

FIG. 2C is a flowchart of a method for checking the sensor current inthe method of FIG. 2A.

FIG. 2D is a flowchart of a method for checking the sensor temperaturein the method of FIG. 2A.

FIG. 2E is a flowchart of a method for detecting a potential droppedsensor (or when a sensor is dropped) in the method of FIG. 2A.

FIG. 3A is a partially transparent elevation view of a storagecompartment (sometimes referred to as a “garage”) for the imaging sensorin the imaging system of FIG. 1A.

FIG. 3B is a partially transparent overhead view of the storagecompartment of FIG. 3A.

FIG. 3C is a perspective view of an alternative example of an imagingsensor storage without an imaging sensor.

FIG. 3D is a perspective view of the alternative example of the imagingsensor storage of FIG. 3C with an imaging sensor therein.

FIG. 4 is a flowchart of a method for transitioning between operatingstates of the imaging system of FIG. 1A based on whether the sensor isdetected in the storage compartment of FIGS. 3A and 3B.

FIG. 5 is a flowchart of a method for transitioning between operatingstates of the imaging sensor of FIG. 1A or FIG. 1B based on anacceleration detected by the multi-dimensional sensor of the imagingsensor.

FIG. 6A is a perspective view of a sensor positioner for holding animaging sensor in a first position for capturing an image.

FIG. 6B is a perspective view of a second sensor positioner for holdingthe imaging sensor in a second position for capturing an image.

FIG. 7 is a flowchart of a method for transitioning between operatingstates of the imaging system of FIG. 1A based on a detection of acoupling between the imaging sensor and a sensor holder of FIG. 6.

FIG. 8 is a flowchart of a method for transitioning between operatingstates of the imaging system of FIG. 1A based on a detection of aspecific movement of the imaging sensor based on an output of themulti-dimensional sensor.

FIG. 9 is a flowchart of a method for detecting when the imaging sensorof the imaging system of FIG. 1A is placed in the mouth of a patientbased on an output of the multi-dimensional sensor.

FIG. 10 is a flowchart of a method for detecting possible damage to thesensor housing in the imaging system of FIG. 1A based on an air pressuredetected by the multi-dimensional sensor.

FIG. 11 is a state diagram of transitions between multiple operatingstates in the imaging system of FIG. 1A based on outputs from themulti-dimensional sensor.

DETAILED DESCRIPTION

Before any embodiments are explained in detail, it is to be understoodthat the invention is not limited in its application to the details ofconstruction and the arrangement of components set forth in thefollowing description or illustrated in the following drawings. Otherembodiments and ways of being practiced or of being carried out arepossible.

FIG. 1A illustrates an example of an imaging system 100. In the examplesdiscussed herein, the imaging system 100 is a dental imaging system foruse with an intra-oral imaging sensor. However, in otherimplementations, the imaging system 100 may be configured for othermedical or non-medical imaging purposes. The imaging system 100 includesan imaging system controller computer 101, which, in someimplementations, includes software executed on a personal computer,tablet computer, or other computing device. The imaging systemcontroller computer 101 includes an electronic processor 103 and amemory 105. In one example, all or part of the memory 105 isnon-transitory and computer readable and stores instructions that areexecuted by the electronic processor 103 to provide the functionality ofthe imaging system controller computer 101, for example, as presented inthis disclosure.

In the example of FIG. 1A, the imaging system controller computer 101 iscommunicatively coupled to a display 106. The system controller computer101 generates a graphical user interface that is output on the display106. As discussed in greater detail below, the graphical user interfaceis configured to receive various inputs from a user and to outputinstructions, data, and other information to the user. Although thedisplay 106 is shown as a separate unit coupled to the imaging systemcontroller computer 101 in the example of FIG. 1A, in otherimplementations, the display 106 is integrated into the same housing asthe imaging system controller computer 101, for example, where theimaging system controller computer 101 is implemented as a laptopcomputer or a tablet computer.

In the example of FIG. 1A, the imaging system controller computer 101 iscommunicatively coupled to an x-ray source 107 and an imaging sensor108. The imaging sensor 108—in this example, an intra-oral dentalimaging sensor—includes an imaging sensor housing 109. An image sensingcomponent is positioned within the imaging sensor housing 109 and isconfigured to capture data that is then used to generate an image. Theexample of FIG. 1A includes a scintillator 111, a fiber optic plate 113,and an image sensor array 115 as the image sensing component positionedwithin the imaging sensor housing. In response to receiving x-rayradiation, the scintillator 111 produces photons that pass through thefiber optic plate 113. The image sensor array 115 detects the photonsdirected by the fiber optic plate 113 and outputs data used to generatean x-ray image. Other implementations may include other image detectioncomponents including, for example, a direct conversion detector (e.g., aphoton counter) that is configured to operate without a scintillatorand/or a fiber optic plate.

A sensor electronic processor 117 is also positioned within the imagingsensor housing 109 and is communicatively coupled to the image sensorarray 115 to receive signals indicative of the detected x-ray radiation.In some implementations, the sensor electronic processor 117 is alsocoupled to a sensor memory 119. In certain embodiments, the sensorelectronic processor 117 is provided as a field programmable gate arraywhile, in other embodiments, the sensor electronic processor 117 is adifferent type of processor and the sensor memory 119 is anon-transitory computer-readable memory which stores instructions thatare executed by the sensor electronic processor 117 to provide orperform certain functions as described herein.

In the example of FIG. 1A, the sensor electronic processor 117 iscommunicatively coupled with an interface microcontroller 121. In theexample illustrated, the interface microcontroller 121 is alsopositioned within the imaging sensor housing 109 and is configured toprovide communication between the sensor electronic processor 117 andthe imaging system controller computer 101 as discussed in greaterdetail below. In some implementations, the imaging system controllercomputer 101 is selectively couplable to the sensor electronic processor117 and/or the interface microcontroller 121 by a wired or wirelessconnection including, for example, a USB cable or a Wi-Fi connection.

The image sensor housing 109 also includes a multi-dimensional sensor123 providing information about the placement, movement, and operationof the imaging sensor 108. In the example of FIG. 1A, themulti-dimensional sensor 123 includes a three-dimensional accelerometer125 configured to output a signal indicative of a magnitude anddirection of acceleration in three-dimensional space. Themulti-dimensional sensor 123 also includes a three-dimensionalgyroscopic sensor 127 and a three-dimensional magnetometer 129.

In various implementations, the imaging sensor 108 may also includeadditional sensor components. In the particular example of FIG. 1A, themulti-dimensional sensor 123 includes a temperature sensor 131configured to output a signal indicative of a temperature of the imagingsensor 108. The imaging sensor 108 also includes a current/voltagemonitor circuit 133 configured to output a signal indicative of acurrent and/or a voltage of the supplied power provided to the imagingsensor 108. The imaging sensor 108 also includes an air pressure sensor135 configured to output a signal indicative of an air pressure withinthe imaging sensor 108. In some implementations, the current/voltagemonitor circuit 133 is not positioned within the imaging sensor housing109 and instead is provided in a separate housing that is externallycoupled to the imaging sensor housing 109.

In the example of FIG. 1A, the current/voltage monitor circuit 133 andthe air pressure sensor 135 are provided as separate components and arenot integrated into the multi-dimensional sensor 123. However, in otherimplementations, the current/voltage monitor circuit 133, the airpressure sensor 135, and the temperature sensor 131 may be integratedinto the multi-dimensional sensor 123. Conversely, in someimplementations, the accelerometer 125, the gyroscopic sensor 127, themagnetometer 129, the temperature sensor 131, the current/voltagemonitor circuit 133, and the air pressure sensor 135 are all providedwithin the imaging sensor housing 109 as separate components without anysingle internal structure or housing identifiable as a“multi-dimensional sensor.” In those implementations, themulti-dimensional sensor 123 refers collectively to one or more sensorcomponents provided within the imaging sensor housing 109. Lastly,although the example of FIG. 1A presents a specific list of types ofsensor components within the imaging sensor housing 109, in otherimplementations, the imaging sensor 108 may include more, fewer, ordifferent sensor components.

In the imaging system 100 illustrated in FIG. 1A, the imaging systemcontroller computer 101 monitors the outputs from the sensors positionedwithin the imaging sensor housing 109 and operates the variouscomponents based at least in part on the outputs from the sensors. Inparticular, as described in greater detail below, the imaging systemcontroller computer 101 operates the imaging sensor 108 in one of aplurality of different operating states and transitions between theoperating states based at least in part on outputs from the sensors ofthe imaging sensor 108. In some implementations, the plurality ofdifferent operating states includes one or more “low power” states, oneor more “ready” states, and one or more “armed” states.

When operating in a “low power” state, electrical power provided to theimaging sensor 108 and/or the electrical power consumed by variouscomponents of the imaging sensor 108 is reduced and somefunctions/operations of the imaging sensor 108 are prohibited orrestricted (barring a manual override). For example, in someimplementations, the imaging sensor 108—particularly the image sensorarray 115—cannot be armed when the imaging sensor 108 is operated in the“low power” state. Instead, the imaging sensor 108 must first transitionto a “ready” state in response to a determination that a first statetransition criteria has been satisfied. When operating in the “ready”state, the imaging sensor 108 is not yet armed, but can be transitionedinto the “armed” operating state in response to an input or a conditiondetected by the imaging system controller computer 101 indicating that asecond state transition criteria has been satisfied. In someimplementations, electrical power provided to one or more of the sensorcomponents in the imaging sensor housing 109 is also reduced ordisconnected while the imaging sensor 108 is operating in the “lowpower” state.

In some implementations, the communication interface between the imagingsensor 108 and the imaging system controller computer 101 is disabledwhen the imaging sensor 108 is operating in the “low power” state. Forexample, in the system of FIG. 1A, the interface microcontroller 121 maybe turned off or powered down when the imaging sensor 108 enters the“low power” state. Alternatively, in some implementations, the interfacemicrocontroller 121 is itself configured to adjust how it controls theconnection between the imaging system controller computer 101 and theinterface microcontroller 121 based on whether the imaging sensor 108 isoperating in the “low power” state.

In the example of FIG. 1A, the sensor electronic processor 117 monitorsthe output of the various sensor components and may be triggered toinitiate an “interrupt” routine and/or output an “interrupt” flag inresponse to detecting that a state transition criteria has beensatisfied as described in further detail below. In this example, theinterface microcontroller 121 resumes operation in response to theinterrupt flag output by the sensor electronic processor 117 andcommunication between the imaging sensor 108 and the imaging sensorcontroller computer 101 is restored. Accordingly, although several ofthe examples presented below discuss functionality performed andexecuted by the electronic processor 103 of the imaging systemcontroller computer 101, in other implementations, this functionality(including the detection of state transition criteria and thetransitions between operating state) is provided in full or in part byanother electronic processor—for example, the sensor electronicprocessor 117.

FIG. 1A generally illustrates the control logic within the imagingsensor 108 as a sensor electronic processor 117 (that both receivescaptured image data from the image sensor array 115 and monitors theoutputs of the other sensor components within the imaging sensor 108)and an interface microcontroller 121 (that controls communicationbetween the imaging sensor 108 and the imaging system controllercomputer 101). However, this control functionality may be implementedusing one or more other processing devices. For example, in someimplementations the functionality described in reference to the sensorelectronic processor 117 and the interface microcontroller 121 isprovided by a single microcontroller component positioned within theimaging sensor housing. Conversely, in other implementations, thefunctionality described in reference to the sensor electronic processor117 is distributed across two or more controllers positioned within theimage sensor housing 109 and/or within the multi-dimensional sensor 123.

FIG. 1B illustrates an example of an imaging sensor 150 that includesthree separate controllers. The first controller is an interfacemicrocontroller 151 that is communicatively coupled to a data bus 153and is configured to manage communications between the imaging sensor150 and the imaging system controller computer (not pictured). In someimplementations, the interface controller 151 is a USB controller and isconfigured to provide communications between the imaging sensor 150 andan external computer system through a wired USB cable interface. Theinterface controller 151 is directly coupled to a storage memory 155 andis coupled to a boot memory 157 through the data bus 153.

The second controller in the example of FIG. 1B is an image acquisitionfield programmable gate array (FPGA) 159. The image acquisition FPGA 159is directly coupled to the image sensor array 161 (or other imagesensing component). Image data captured by the image sensor array 161 isstreamed via the image acquisition FPGA 159 to an image memory 163. Inthis example, the image memory 163 includes an SRAM device. The imageacquisition FPGA 159 is configured to handle image data transfer betweenthe image sensor array 161, the image memory 163, and the interfacemicrocontroller 151. In some implementations, the image acquisition FPGAis also configured to implement various control and monitoring functionsfor the image sensor array 161 including, for example, a dose sensingalgorithm.

Various other sensor components are also coupled to the data bus 153 inthe example of FIG. 1B. An input power measurement circuit 165 isconfigured to monitor the voltage and current operating power providedto the imaging sensor 150 and to output a signal indicative of themeasured voltage and current to the data bus 153. An air pressure sensor167 is positioned within a housing of the imaging sensor 150 and coupledto provide an output signal to the data bus 153. In someimplementations, the air pressure sensor 167 is configured to measure anabsolute air pressure value and output the measured value to the databus 153 while, in other implementations, the air pressure sensor 167 isconfigured to output a signal to the data bus 153 indicative of a changein the internal air pressure and/or to output an air pressure interruptflag to the data bus 153 in response to detecting a change in airpressure that exceeds a threshold.

In the example of FIG. 1B, a nine-dimensional (9D) sensor 169 is alsocommunicatively coupled to the data bus 153. Like the multi-dimensionalsensor 123 in the example of FIG. 1A, the 9D sensor 169 includes athree-dimensional gyroscopic sensor 171, a three-dimensionalaccelerometer 173, and a three-dimensional magnetometer 175 providingmeasurement data indicative of nine dimensions of movement, position,and orientation of the imaging sensor 150. The 9D sensor 169 alsoincludes a temperature sensor 177.

The third controller in the example of FIG. 1B is a 9D sensor controller179 positioned within the 9D sensor 169. The 9D sensor controller 179 isconfigured to monitor and control the various sensor components of the9D sensor 169 and to output data/signals to the data bus 153 indicativeof the conditions and parameters measured by the sensor components. The9D sensor controller 179 also includes one or more dedicated “interrupt”pins coupled directly to the interface microcontroller 151. In someimplementations, the 9D sensor controller 179 is configured to monitorthe outputs from one or more of the sensor components of the 9D sensor169, to determine whether certain state transition criteria issatisfied, and to output an “interrupt” flag signal to the interfacemicrocontroller 151 in response to determining that the state transitioncriteria has been satisfied. This “interrupt” flag signal output by the9D sensor controller 179 to the interface microcontroller 151 can, insome implementations, cause the interface microcontroller 151 totransition from one operating state to another (for example, atransition from the “low power” state to a “ready” state as discussedabove).

Accordingly, although certain examples presented in this disclosurerefer generally to determinations made by or functionality provided bythe sensor electronic processor 117, in various other implementations,this functionality can be implemented by one or more differentcontroller components internal to the imaging sensor 108/150 or, in somecases, within the imaging system controller computer 101 depending onthe particular control logic architecture that is implemented. Forexample, an “interrupt routine” may refer to a sub-routine orfunctionality provided in response to a detected condition. An“interrupt signal” or “interrupt flag” refers to an output (for example,a binary output) from one controller or sensor that, when received byanother logic component, causes the component to perform or modify thefunctionality of the system (for example, initiating execution of an“interrupt routine”).

In some implementations, before transitioning from the “low power” stateinto the “ready” state or, in other implementations, beforetransitioning from the “ready” state into the “armed” state, the imagingsystem controller computer 101 or the sensor electronic processor 117implements an error condition check routine to ensure that the imagingsensor 108 is operating properly. In other implementations, an errorcondition check routine is performed periodically while the imagingsensor 108 is operated in a single operating state—for example, aftereach image is captured while operating in the “armed” state. In stillother implementations, an error notification can cause the electronicprocessor to automatically launch other system check routines orautomated self-correction routines. In the discussion below,functionality or steps that are described as being performed by the“imaging system” are implemented, in various embodiments, by one or moreof the controllers of the imaging system including, for example, thesensor electronic processor 117, the interface microcontroller 121, theelectronic processor 103 of the imaging system controller computer 101,or the 9D sensor controller 179 of the 9D sensor 169.

An example error condition check routine is illustrated in FIGS. 2Athrough 2E. Beginning in FIG. 2A, after the error condition checkroutine is initiated (block 201), the imaging system 100 first performsa “voltage” check (block 203). If the imaging sensor 108 passes thevoltage check, the imaging system 100 performs a “current” check (block205). If the imaging sensor 108 passes the current check, then theimaging system 100 performs a “temperature” check (block 207). If theimaging sensor 108 passes the temperature check, then the imaging system100 perform an “acceleration” check (block 209). If the imaging sensor108 passes each of the error condition check routines, then the imagingsystem 100 continues with the operation of the imaging sensor 108 (forexample, continuing to operate in the “armed” state or transition intothe “armed” state).

FIG. 2B illustrates an example of the “voltage check” routine in greaterdetail. Based on an output from the current/voltage monitor circuit 133,the imaging system 100 determines a voltage of the electrical powerprovided to the imaging sensor 108, for example, through the USB cablecoupled to the imaging system controller computer 101 (block 211). Ifthe detected voltage does not exceeds a first voltage threshold (V1)(block 213), then the imaging system 100 determines that there is anerror condition either within the imaging sensor 108 or the cableconnecting the imaging sensor 108 to its power source. In response tothis detected condition, the imaging system 100 disarms the sensor and,in some implementations, prevents the sensor from transitioning into the“armed” state (block 215). A “low voltage” notice is output to the user(block 217). The “low voltage” notice can be output, for example, as agraphical notice shown on a display coupled to the imaging systemcontroller computer 101. The “low voltage” notice, in someimplementations, displays a value of the detected voltage and instructsthe user on possible corrective measures. For example, the “low voltage”notice may instruct the user to try connecting the imaging sensor 108 toanother USB port, connecting the imaging sensor 108 to a differentcomputer/imaging system controller computer 101, or connecting theimaging sensor 108 to the imaging system controller computer 101 using adifferent USB cable. The “low voltage” notice may also instruct the userto contact technical support if the condition persists. In someimplementations, detected error/fault conditions (for example, the “lowvoltage” condition and other conditions described below) are recorded toa log file used to track errors/faults of an imaging sensor 108.

Similarly, if the imaging system 100 determines that the detectedvoltage exceeds a second voltage threshold (V2) that is higher than thefirst voltage threshold (block 219), then the imaging system 100 detectsa “high voltage” condition on the imaging sensor 108. The imaging system100 either disarms the sensor and, in some implementations, prevents thesensor from transitioning into the “armed” state (block 221). A “highvoltage” notice is output to the user (block 223). Because a “highvoltage” condition can potentially damage the imaging sensor 108hardware, the “high voltage” notice instructs the user to promptlyunplug the imaging sensor 108 from the power supply to prevent damage.In some implementations, based on information including, for example,the magnitude of the detected voltage, the “high voltage” noticeincludes user instructions informing the user to try connecting theimaging sensor 108 to a different computer or to contact technicalsupport. In still other implementations, the imaging system 100 may beconfigured to transmit an error message directly to a technical supportsystem and to include in the error message an identification andlocation of the imaging system controller computer 101 that detected theerror condition and an indication of the magnitude of the detectedvoltage.

If, however, the detected voltage of the electrical power provided tothe imaging sensor 108 is between the first voltage threshold and thesecond voltage threshold, then then imaging sensor 108 has passed the“voltage check” portion of the test. The imaging system 100 thencontinues to the “current check” routine (block 225).

FIG. 2C illustrates the “current check” component (block 205 of FIG. 2A)of the error condition check routine. In some implementations, if theimaging sensor 108 does not pass the “voltage check” component (block203 of FIG. 2A), then the imaging system 100 disarms the imaging sensor108 without performing the current check component. However, afterpassing the “voltage check” component, the imaging system 100 begins thecurrent check component by determining the current of the electricalpower provided to the imaging sensor 108 (block 227). If the current isbelow a first current threshold (I1) (block 229), then the imagingsystem 100 determines that a “low current” condition exists and, inresponse, the imaging sensor 108 is disarmed or prohibited from arming(block 231) and a “low current” notice is output on the graphical userinterface of the imaging system controller computer 101 (block 233). The“low current” notice may include a magnitude of the determined current,an instruction for troubleshooting the detected problem (for example,try another USB port, another computer, or another USB cable), or aninstruction to contact technical support.

If the current is above the first current threshold (I1), then theimaging system 100 determines whether the detected current is above asecond current threshold (I2) that is greater than the first currentthreshold (block 235). If so, the imaging system 100 determines that a“high current” condition exists and, in response, disarms the imagingsensor 108 and, in some implementations, prevents the imaging sensor 108from arming (block 237). A “high current” notice is output to the user(block 239). Because a high current can potentially damage the hardwareof the imaging sensor 108, in some implementations, the “high current”notice instructs the user to disconnect the sensor immediately toprevent damage. The “high current” notice may also instruct the user totry connecting the imaging sensor 108 to another computer (for example,imaging system controller computer 101), to connect using another cable,or to contact technical support.

If the detected current is between the first current threshold and thesecond current threshold, the imaging system 100 then determines a rateof change of the detected current. The rate of change of the detectedcurrent is determined based on the most recently detected current andone or more previously detected currents. In some implementations, acurrent log file is maintained so that the rate of change of thedetected current can be tracked over longer periods of time byextracting or reading data from the log file. The rate of change of thecurrent is compared to a rate of change current threshold (I3) (block241). In some implementations, this comparison indicates whether thecurrent has increased by more than the defined threshold with respect toa baseline current determined at the time that the imaging sensor 108was plugged into the power source (for example, the imaging systemcontroller computer 101). If the rate of change exceeds the rate ofchange current threshold, the imaging sensor 108 is disarmed or, in someimplementations, is prevented from arming (block 243). A “high currentchange” notice is output to the user on the graphical user interface ofthe imaging system controller computer 101 (block 245). The “highcurrent change” notice instructs the user to disconnect the imagingsensor 108 in order to prevent damage and, in some implementations,provides further instructions for troubleshooting/mitigation including,for example, contacting technical support.

If the imaging sensor 108 passes all three of these checks and thesensor is already armed (block 247), then the imaging system 100continues to operate the imaging sensor 108 in its current operatingstate or continues to the other components of the error condition checkroutine (block 249). However, if the imaging sensor 108 is not yet armed(at block 247), then the current check component includes anotherverification test. The imaging system 100 arms the imaging sensor 108(block 251) and measures the current immediately after arming theimaging sensor 108 (block 253). If the current detected immediatelyafter arming the imaging sensor 108 exceeds a fourth current threshold(I4) (block 255), then the imaging sensor 108 is disarmed (block 257)and an “incomplete arming” notice is output to the user indicating thatan error condition was detected based on the detected electrical currentduring the arming process (block 259). The “incomplete arming” noticeindicates to the user that the imaging sensor 108 was not successfullyarmed and that x-ray images will not be captured. In someimplementations, the “incomplete arming” notice may also provideadditional instructions for mitigating/troubleshooting the errorcondition including, for example, trying another USB port, computer, orUSB cable or contacting technical support.

However, if the current detected immediately after arming the imagingsensor 108 is below the fourth current threshold (I4) (block 255), thenthe imaging system 100 proceeds with operating the imaging sensor 108 inthe “armed” state and/or proceeds to the next test in the errorcondition check routine. In the example of FIGS. 2A through 2E, animaging sensor 108 that is transitioning from the “ready” state to the“armed” state becomes “armed” during the current check mechanism andremains armed for the “temperature” check component (block 207 in FIG.2A) and the acceleration check (block 209 in FIG. 2A). However, in someother implementations, the portion of the current check component thatcompares the detected current immediately after the imaging sensor 108is armed to a fourth current threshold (I4) (block 255) is delayed untilafter one or more additional tests are performed while the imagingsensor 108 is unarmed.

After completing the voltage check component (block 203 in FIG. 2A) andthe current check component (block 205 in FIG. 2A), the imaging system100 applies a temperature check to the imaging sensor 108. In thisexample, the temperature check is applied after the imaging sensor 108has been armed. However, in other implementations, the imaging system100 performs the temperature check before arming the imaging sensor 108.If the imaging sensor 108 passes the voltage check and the current checkcomponents, then an abnormal temperature detected during the temperaturecheck may indicate a problem with both the current of the imaging sensor108 and the voltage/current monitor circuit 133.

In performing the temperature check component, the imaging system 100first determines a temperature of the sensor (block 261) and thencompares the detected temperature to a first temperature threshold (T1)(block 263). If the detected temperature exceeds the first temperaturethreshold, then the imaging system 100 determines that an errorcondition exists, disarms the imaging sensor 108 (or, in someimplementations, prevents the imaging sensor 108 from arming) (block265) and outputs a “high temperature” notice to the user on thegraphical user interface of the imaging system controller computer 101(block 267). Because a high temperature may be indicative of a highcurrent or an electrical short in the circuitry of the imaging sensor108, the “high temperature” notice in some implementations instructs theuser to immediately disconnect the imaging sensor 108 from the powersource (for example, the imaging system controller computer 101) and tocontact technical support. In some implementations, the imaging system100 then continues to prevent the imaging sensor 108 from being re-armedfor a defined delay period to allow the imaging sensor 108 to cool(block 268).

If the temperature of the imaging sensor 108 is below the firsttemperature threshold (T1), the imaging system 100 then considerswhether there is an abnormal rate of temperature change in the imagingsensor 108. The imaging system 100 determines a rate of temperaturechange (block 269) based on the most recently detected temperature andone or more earlier detected temperatures and compares the calculatedrate of temperature change to a temperature change threshold (T2) (block271). If the rate of temperature change is below the temperature changethreshold, then the imaging sensor 108 has passed the temperaturecomponent of the error condition check routine and the imaging system100 continues to operate the imaging sensor 108 (block 273). However, ifthe rate of temperature change exceeds the threshold, the imaging system100 disarms the imaging sensor 108 (or prevents arming of the imagingsensor 108) (block 273) and outputs a “temperature change” notice to theuser on the graphical user interface of the imaging system controllercomputer 101 (block 277). The “temperature change” notice may instructthe user to immediately disconnect the imaging sensor 108 to preventdamage and may also instruct the user to contact technical support.

Lastly, if the imaging sensor 108 has passed the voltage component, thecurrent component, and the temperature component of the error conditioncheck routine, then the imaging system 100 evaluates the output of theaccelerometer 127 to determine whether the imaging sensor 108 has beendropped during or prior to the arming process. The imaging system 100determines an absolute magnitude of acceleration based on the output ofthe accelerometer 125 (block 281). In some implementations, the imagingsystem 100 determines a maximum acceleration detected since the imagingsensor 108 transitioned from the “low power” state into the “ready”state or since the last “acceleration check” was performed. If thedetected acceleration is less than the acceleration threshold (block283), then the imaging sensor 108 is armed and continues its normaloperation (block 285). However, if the detected acceleration exceeds anacceleration threshold indicative of a sudden drop or other potentiallydamaging impact, then an “potential damage” notice is output to the useron the graphical user interface of the imaging system controllercomputer 101 (block 287). The “potential damage” notice indicates that apotentially damaging event was detected and instructs the user tovisually inspect the imaging sensor housing 109 for visible damage. Insome implementations, the imaging sensor 108 continues to operate in the“armed” state even after a potential damage” event is detected as longas the other components of the error condition check routine have passedsuccessfully. Furthermore, as noted above, in some implementations, thedetermination of whether the output of the accelerometer exceeds theacceleration threshold indicative of a sudden drop is performed by alogic component positioned within the imaging sensor housing 109 andconfigured to output an interrupt in response—this enables theacceleration indicative of a “drop” event to be detected quickly withoutthe need for communication between the imaging sensor 108 and theimaging system controller computer 101 and further processing by theimaging system controller computer 101. In some embodiments, this logiccomponent is provided as the sensor electronic processor 117 (of FIG.1A), the 9D sensor controller 179 (of FIG. 1B), or another logiccircuit.

The example discussed above in reference to FIGS. 2A through 2E is justone example of an error condition check routine that is applied to animaging sensor 108. In other implementations, the steps may be performedin another order and may include more, fewer, or alternative tests andsteps. In addition, although most of the failed tests discussed aboveresult only in a notice displayed to the user on the graphical userinterface of the imaging system controller computer 101, otherimplementations may provide automated mitigation steps. For example, theimaging system 100 may be configured to automatically disconnect theimaging sensor 108 from the power source if one or more specific testsare not passed. Additionally, instead of instructing a user to contacttechnical support if a problem persists, the imaging system 100 may beconfigured to automatically transmit a message to a technical supportsystem including an identification and/or location of the imaging systemcontroller computer 101. The message may also include other detailsabout the failed test (including the sensor output reading that causedthe imaging sensor 108 to fail the test).

As discussed above, one or more of the error condition check routinesillustrated in FIGS. 2A through 2E above may be performed periodicallywhile an imaging sensor 108 is operated in an “armed” state or may beperformed as the imaging sensor 108 is transitioned from one state toanother. However, the imaging system 100 may be configured to use theoutput from the various sensor components of the imaging sensor 108 totransition from one operating state to another. For example, FIGS. 3Aand 3B illustrate an imaging system housing 301 that includes a “garage”303 or “storage holder” for storage of the imaging sensor 108 when it isnot in use. A permanent magnet 305 is integrated into the imaging systemhousing 301 and positioned to apply a magnetic field to the imagingsensor 108 when it is stored in the “garage” 303. The magnetic fieldgenerated by the permanent magnet 305 has a magnitude and vectordirection that can be detected and identified based on the output of themagnetometer 129 of the imaging sensor 108.

As illustrated in FIG. 4, the imaging system 100 is configured totransition between the “low power” state and the “ready” state based onwhether the output of the magnetometer 129 indicates that the imagingsensor 108 is positioned within the garage 303 of the imaging systemhousing 301. The imaging system 100 periodically processes the outputsignal from the magnetometer 129 to detect a strength and vectordirection of a magnetic field relative to the imaging sensor 108 (block401). If the imaging sensor 108 is not currently operating in a “lowpower” state (block 403), then the detected magnetic field is analyzedto determine whether the detected magnetic field is indicative ofplacement of the imaging sensor 108 in the “garage” 303 or storageholder (block 405). If a magnetic field indicative of placement in the“garage” 303 is detected, then the imaging sensor 108 is transitionedinto the “low power” state (block 407). However, if the magnetic fieldindicative of placement in the “garage” 303 is not detected, then theimaging sensor 108 remains in the “ready” state (block 409).

When the imaging sensor 108 is already operating in the “low power” mode(block 403), the imaging system 100 determines whether the detectedmagnetic field is indicative of removal of the imaging sensor 108 fromthe “garage” 303 (block 411). In some embodiments, a magnetic fieldindicative of removal of the imaging sensor 108 from the “garage” 303 isone in which the magnitude of the detected magnetic field drops below adefined threshold and/or the vector direction of the detected magneticfield deviates from the vector direction of the magnetic field expectedto be applied by the permanent magnet 305 by a predetermined amount. Ifa magnetic field indicative of removal of the imaging sensor 108 fromthe “garage” 303 is detected (block 411), then the imaging sensor 108 istransitioned from the “low power” mode into the “ready” mode (block409). However, if the detected magnetic field continues to indicate thatthe imaging sensor 108 is placed within the “garage” 303, then theimaging sensor 108 remains in the “low power” state (block 407).

In some implementations, the imaging sensor 108 “wakes up” (for example,transitions from the “low power” state into the “ready” state) basedonly on a detected change in the magnetic field applied by the permanentmagnet 305. However, in some implementations, additional or alternativeinformation provided by the sensor components of the imaging sensor 108are used to determine whether to transition the imaging sensor 108 intothe “ready” mode. For example, as also illustrated in FIG. 4, while theimaging sensor 108 is operating in the “low power” state, the imagingsystem 100 may be configured to periodically detect the acceleration ofthe imaging sensor 108 based on the output of the accelerometer 125. Ifthe detected acceleration exceeds a “wake up” threshold (block 413), theimaging sensor 108 is transitioned into the “ready” state (block 409)and, if the detected acceleration is below the “wake up” threshold, theimaging sensor 108 remains in the “low power” state (block 407). Asillustrated in the example of FIG. 4, the magnetic field andacceleration “wake up” criteria are applied in parallel in someembodiments and a condition meeting either criterion will cause theimaging sensor 108 to transition into the “ready” state. However, inother implementations, the magnetic field and acceleration “wake up”criteria are applied in series and both criteria must be satisfiedbefore the imaging sensor 108 will be transitioned into the “ready”state.

As discussed above, in some implementations, the determinationsdescribed in reference to FIG. 4 are performed by the imaging systemcontroller computer 101 based on data received from the imaging sensor108. However, in other implementations—for example, in implementationswhere communication between the imaging sensor 108 and the imagingsystem controller computer 101 are disabled while the imaging sensor 108is operated in the low power mode—some or all of the state transitiondeterminations are made by a logic component included within the imagingsensor 108 (for example, the sensor electronic processor 117 in theexample of FIG. 1A). In still other implementations, one logic componentpositioned within the imaging sensor housing 109 and/or themulti-dimensional sensor 123 (for example, the 9D sensor controller 179in the example of FIG. 1B) is configured to generate an “interrupt” flagin response to certain measured conditions. For example, in reference tothe method of FIG. 4, the 9D sensor controller 179 of FIG. 1B may beconfigured to generate an interrupt flag when the output of theaccelerometer 173 indicates that the acceleration of the imaging sensor150 exceeds the “wake up” threshold. This interrupt flag causes theimaging sensor 150 to transition from the low power state into the readystate, in part, by the interface microcontroller 151 restoringcommunication between the imaging sensor 150 and the imaging systemcontroller computer 101. When the state transition condition isinitiated by an interrupt (as in the example of FIG. 1B), the imagingsensor 150 may not need to communicate acceleration data to the imagingsystem controller computer 101 as frequently as might be required if theimaging system controller computer 101 were periodically monitoring theacceleration of the imaging sensor 108 to determine whether the “wakeup” threshold is exceeded. In some implementations, no acceleration datais communicated from the imaging sensor 108 to the imaging systemcontroller computer 101 while the imaging sensor 108 is operating in thelow power state.

In the example of FIGS. 3A and 3B, the permanent magnet 305 ispositioned above the “garage” 303 or permanently integrated into a wallor surface of the garage. However, in other implementations, thepermanent magnet 305 can be positioned at other locations to provide aunique and detectable magnetic field when an imaging sensor 108 ispositioned within the “garage” 303. Similarly, although the storageholder is illustrated in FIGS. 3A and 3B as a “garage,” the storageholder can be provided in other configurations in other implementationincluding, for example, as a “holster” or a clip positioned on the sideof the imaging system housing 301. In still other implementations, thestorage holder or “garage” 303 may be provided as a housing that iscompletely separate from the imaging system controller computer 101 andmay be positionable near the workspace of the dental practitioner foreasy access. For example, FIGS. 3C and 3D illustrate an example of animage sensor storage 311 where the imaging sensor 108 is supportedagainst a backplate 313 and by a pair of support arms 315. In thisexample, the permanent magnet is incorporated into the backplate 313 togenerate a magnetic field and the imaging sensor 108 is not fullyenclosed when placed in the image sensor storage 311. FIG. 3C shows onlythe image sensor storage 311 and FIG. 3D shows the image sensor storage311 with the imaging sensor 108 positioned therein.

Although the example of FIGS. 3A and 3B discuss using a permanent magnetto detect whether the imaging sensor 108 is placed in the “garage” 303and, based on that determination, transition between operating states,in some other implementations, other mechanisms may be used to detectwhether the imaging sensor 108 is in a storage position and totransition between operating states accordingly.

In still other implementations, the magnetometer 129 may be disabledwhen the imaging sensor 108 is operating in the “low power” state.Therefore, the determination of when to transition the imaging sensor108 into the “ready” state is based on criteria from another sensor orsensors—for example, the acceleration criteria (block 413) may beapplied as the only test to determine when to transition the device fromthe “low power” state into the “ready” state.

Similarly, in some implementations, acceleration as detected based onthe output from the accelerometer 125 may govern the transition betweenthe “ready” state and the “low power” state even without a determinationthat the imaging sensor 108 has been placed in the “garage” 303. Thismay occur, for example, when a dental practitioner places the imagingsensor 108 on a counter or table. As illustrated in FIG. 5, the imagingsystem 100 determines an absolute magnitude of acceleration based on theoutput from the accelerometer 125 (block 501). If the detectedacceleration does not equal zero (indicating that the device is moving)(block 503), then the imaging sensor 108 is operated in the “ready”state. Conversely, if the detected acceleration indicates that theimaging sensor 108 is stationary (block 503), then the imaging sensor108 is placed in the “low power” state (block 507).

In some implementations, the imaging sensor 108 is not transitioned fromthe “ready” state into the “low power” state immediately upon detectionof an acceleration equal to zero and, instead, the zero accelerationmust be detected continuously for a defined period of time before theimaging sensor 108 is transitioned into the “low power” state based onthe criteria of FIG. 5. In other implementations, the state transitioncriteria described in reference to FIG. 5 is not applied if the imagingsensor 108 is operating in the “armed” state and the imaging sensor 108must first be operating in the “ready” state before the imaging sensor108 can transition into the “low power” state based on a detectedacceleration of zero.

State transitions may also be governed by detecting and identifyingother magnetic fields acting upon the imaging sensor 108. For example,FIGS. 6A and 6B each shows a sensor positioner configured to hold theimaging sensor 108 in a position for capturing a specific type of image.The first sensor positioner 601, illustrated in FIG. 6A, includes abackplate 603 and a pressure arm 605. To selectively couple the imagingsensor 108 to the first sensor positioner 601, the imaging sensor 108 isplaced between the backplate 603 and the pressure arm 605. The imagingsensor 108 is held in place by the shape of the backplate 603 andfriction/pressure applied by the pressure arm 605. A first permanentmagnet 607 is also included in the first sensor position at a locationproximal to the imaging sensor 108 when coupled to the sensor positioner601. The first permanent magnet 607 creates a magnetic field of a knownmagnitude and vector direction that is detectable by the magnetometer129 of the imaging sensor 108 when the imaging sensor is coupled to thefirst sensor positioner 601.

The second sensor positioner 611, illustrated in FIG. 6B, also includesa backplate 613 and a pressure arm 615 for selectively coupling theimaging sensor 108 to the second sensor positioner 611. The shape andarrangement of the second sensor positioner 611 is different from thatof the first sensor positioner 601 and is configured for placing theimaging sensor for capturing images of dental structures at a differentlocation in a patient's mouth. The second sensor positioner 611 alsoincludes a second permanent magnet 617. The second permanent magnet 617also generates a magnetic field of a known magnitude and vectordirection that is detectable by the imaging sensor 108 when coupled tothe second sensor positioner 611. However, due to the type andpositioning of the second permanent magnet 617, the magnetic fieldgenerated by the second permanent magnet 617 and detected by themagnetometer 129 of the imaging sensor 108 when coupled to the secondsensor positioner 611 is different from the magnetic field that isgenerated by the first permanent magnet 607 and detected by themagnetometer 129 when the imaging sensor 108 is coupled to the firstsensor positioner 601. Based on these different and known magneticfields, the imaging system 102 is configured to identify, based on theoutput of the magnetometer 129, when the imaging sensor 108 is coupledto a sensor positioner and to identify whether the imaging sensor 108 iscoupled to the first sensor positioner 601 or to the second sensorpositioner 611.

Although the examples illustrated in FIGS. 6A and 6B show the permanentmagnet 607, 617 positioned in or on the backplate 603, 613, in otherimplementations and in other sensor positioners, the permanent magnetcan be positioned in other fixed locations. For example, a permanentmagnet may be positioned on the pressure arm 615 or on anotherstructural portion of the sensor positioner behind or below thebackplate 613.

As illustrated in FIG. 7, a magnetic field applied by a permanent magnetintegrated into a sensor positioner can govern a transition from the“ready” state into the “armed” state and, in some implementations wheremultiple different sensor positioners and/or sensor positionerconfigurations are used to capture a series of images, the detectedmagnetic field can be used to provide automated instructions to a userof the imaging system 100. While the imaging sensor 108 is operating ina “ready” mode (block 701), the output of the magnetometer 129 isanalyzed to determine a magnitude and vector direction of a magneticfield (block 703). The detected magnetic field is analyzed to determinewhether the detected magnetic field indicates a coupling with a sensorpositioner (block 705). If not, then the imaging sensor 108 continues tooperate in the “ready” state (block 701). However if the detectedmagnetic field is indicative of coupling with a sensor positioner (block705), then the type and/or configuration of the sensor positioner isidentified based on the magnitude and vector direction of the detectedmagnetic field (block 707). In response, the imaging sensor 108 is armed(block 709) and, in some implementations, an instruction for placementof the imaging sensor 108 is displayed on the graphical user interfaceof the imaging system controller computer 101. After an image iscaptured (based, for example, on a user-activated or automated trigger)(block 711), the graphical user interface of the imaging systemcontroller computer 101 outputs an instruction for a next image to becaptured (block 713). In some embodiments, the instruction is output asa text instruction shown on the display 106 while, in other embodiments,the instruction is output audibly through a speaker.

In some embodiments, the output instruction also indicates whether a newsensor positioner or a new configuration is required for the next imageto be captured. If the same sensor positioner and the same configurationis to be used for the next image (block 715), the imaging sensor 108remains in the “armed” state and the next image is captured (block 711).However, if a different sensor positioner or a different configurationis needed for the next image (block 715), then the imaging sensor 108 isdisarmed (block 717) and the detected magnetic field is again monitoreduntil a magnetic field is identified that is indicative of a couplingbetween the imaging sensor housing 109 and the sensor positioner (block705).

Although the example of FIG. 7 describes a transition from a “ready”state into an “armed” state, in other implementations, the magneticfield applied by a permanent magnetic incorporated into the sensorpositioner can instead govern other types of state transitionsincluding, for example, a transition from one “ready” state into another“ready” state, from one “armed” state into another “armed” state, orfrom a “low power” state to a “ready” state.

In some implementations, the transition from the “ready” state into the“armed” state can be governed based on outputs from other sensorcomponents of the imaging sensor 108. For example, specific gesturesmade with the imaging sensor housing 109 can be detected based on theoutput from the accelerometer 125 and/or the gyroscopic sensor 127 andused to transition from the “ready” state into the “armed” state. Thistype of gesture detection can also be used to control the state ofapplication software. FIG. 8 illustrates a method for detecting oneexample of a specific gesture that can trigger a transition from a“ready” state into an “armed” state. In this example, the imaging sensor108 is transitioned into the “armed” state if the imaging sensor 108 israised and lowered three times in succession.

Acceleration and/or position data is received from the accelerometer 125and/or the gyroscopic sensor 127, respectively, (block 801) and isanalyzed to determine whether a “raise & lower” gesture has been madewith the imaging sensor 108 (block 803). If so, a counter is incremented(block 805) and, if the counter has not yet been incremented to three(3) (block 807), the imaging system 100 continues to monitor theacceleration/position data (block 801) to detect additional “raise andlower” gestures (block 803). When three successive “raise and lower”gestures are detected and the counter has been incremented to three(block 807), then the imaging sensor 108 is transitioned from the“ready” state into the “armed” state (block 809).

To ensure that the three “raise and lower” gestures are made indeliberate succession, a timeout mechanism is applied. If a timeoutperiod has not yet elapsed since the first “raise and lower” gesture wasdetected (or, in some implementations, since the most recent “raise andlower” gesture was detected) (block 811), the imaging system 100continues to monitor the acceleration/position data (block 801) todetect additional “raise and lower” gestures (block 803). However, ifthe timeout period has expired (block 811), then the counter is reset tozero (block 813). The detection of specific gestures and movements canalso be used to trigger other operations of the imaging systemincluding, for example, resetting a dark current.

FIG. 8 illustrates only one example of a gesture that can be performedwith the imaging sensor 108 and detected based on the outputs from thevarious sensors within the imaging sensor housing 109. In otherimplementations, the imaging system 100 is configured to detect othertypes of gestures instead of three successive “raise and lower”gestures. In some implementations, different gestures can be used to notonly trigger a transition into the “armed” state, but also to indicateto the imaging system 100 which specific type of image (or image series)is to be captured by the imaging system 100. For example, detection of afirst gesture pattern indicates to the imaging system 100 that a firsttype of x-ray image is to be captured and, in response, the graphicaluser interface of the imaging system controller computer 101 outputsinstructions and information relevant specifically to the first type ofx-ray image. Conversely, detection of a second, different gesturepattern indicates to the imaging system 100 that a second type of x-rayimage is to be captured and, in response, the graphical user interfaceof the imaging system controller computer 101 outputs instructions andinformation relevant specifically to the second type of x-ray image orimage series. Alternatively, the imaging system controller computer 101may process or store the captured image data differently based on whichimage type is indicated by the detected gesture pattern.

In some implementations, the imaging system 100 may also be configuredto transition from one state to another by detecting when the imagingsensor 108 has likely been placed within the mouth of a patient. FIG. 9illustrates a method of determining whether the imaging sensor 108 hasbeen placed within the mouth of a patient based on an output from thetemperature sensor 131. Because the temperature detected by thetemperature sensor 131 will likely increase when the imaging sensor 108is placed in the mouth of a patient, the imaging system 100 appliesthree different temperature-based criteria to confirm that the imagingsensor 108 has been moved from a position outside of the patient's mouthto a new position within the patient's mouth.

First, the imaging system 100 determines and stores a temperaturereading based on the output of the temperature sensor 131 (block 901).The present temperature is compared to a temperature threshold (forexample, 98° F.) (block 903). If the imaging sensor 108 has been placedin the mouth of a patient, then the sensed temperature should exceedthis temperature threshold.

Second, the imaging system 100 determines a first derivative of sensedtemperatures based on the most recently detected temperature andpreviously detected temperatures stored on a memory (for example, memory105 or sensor memory 119) (block 905). The calculated first derivativeof the temperature is compared to a rate-of-change threshold (block907). If the imaging sensor 108 has been moved from a position outsideof a patient's mouth (at room temperature) to a position inside thepatient's mouth (at “body” temperature), then the calculated firstderivative should exceed this rate-of-change threshold.

Third, the imaging system 100 determines a second derivative of sensedtemperatures (block 909). This second derivative is indicative of howquickly the rate-of-change of the temperature is increasing and iscompared to an “acceleration” threshold (block 911). Again, if theimaging sensor 108 has been moved from a position outside of thepatient's mouth (at room temperature) to a position inside the patient'smouth (at “body” temperature), then the calculated second derivativeshould indicate a sudden increase in the rate of temperature change andshould exceed this acceleration threshold.

If all three temperature-based criteria are satisfied, the imagingsensor 108 is transitioned into the “armed” state based on theassumption that the imaging sensor 108 has been placed inside apatient's mouth (block 913). However, if any one of the three criteriais not satisfied, the imaging system 100 cannot “confirm” that theimaging sensor 108 has been placed inside a patient's mouth and,therefore, the imaging sensor 108 remains in the “ready” state (block915). Due to ambient temperature fluctuations, some methods fordetermining whether an imaging sensor 108 has been placed in the mouthof a patient based on sensed temperatures may result in false“negatives” causing the imaging sensor 108 to remain in the “ready”state even after the imaging sensor 108 has actually been placed in themouth of the patient. In some embodiments, the user can override a falsenegative and force the imaging sensor 108 to transition into the “armed”state using a switch or input on the graphical user interface of theimaging system controller computer 101 (block 917).

As discussed above in reference to FIGS. 2A-2E, the imaging system 100may be configured to apply one or more error condition check routineswhen the imaging sensor 108 is first connected to the imaging systemcontroller computer 101, in response to (or in preparation for) a statetransition, or periodically while operating in a particular state. Insome implementations, the imaging sensor 108 is equipped with one ormore additional internal sensors that are configured for other types oferror condition detection. For example, FIG. 9 illustrates a method fordetecting potential damage to the imaging sensor housing 109 due tosudden impact on the housing or biting of the housing by a patient basedon an air pressure within the imaging sensor housing 109 detected by theair pressure sensor 135.

In the example of FIG. 10, the imaging system 100 monitors the output ofthe air pressure sensor 135 (block 1001). Because air pressures willchange naturally due to changes in temperature, the imaging system 100determines a temperature-compensated pressure threshold (block 1003) andcompares the detected air pressure to the compensated threshold (block1005). If the detected air pressure remains below the compensatedthreshold, then the imaging system 100 continues its operation (block1007). However, an air pressure that is above the compensated thresholdmay be caused by biting of the imaging sensor housing 109 or anotherpotential damaging impact. Therefore, in response to detecting an airpressure above the compensated threshold (block 1005), the imagingsystem 100 outputs a “Potential Pressure Damage” notice to the user onthe graphical user interface of the imaging system controller computer101 (block 909). In some implementations, this notice instructs the userto visually inspect the imaging sensor housing 109 for damage. In otherimplementations, the imaging system 100 is configured to run anautomated check routine in response to detecting an air pressureindicative of potential damage and, depending on the result of theautomated check routine, will either apply an automated self-correctionor output a notice to the user with further instructions.

In the example of FIG. 10, even after detecting an increased airpressure indicative of a possible damage event, the imaging system 100continues its operation (block 1007) and relies upon the user todetermine whether the imaging sensor housing 109 has been damaged to theextent that usage of the imaging sensor 108 should be stopped. However,in other implementations, the imaging system 100 may be configured todisable the imaging sensor 108 in response to detection of the possibledamage event or to take additional mitigating action before continuingoperation. For example, the imaging system 100 may be configured toautomatically transmit a notice to a technical support system requestingmore substantial inspection or testing of the imaging sensor 108 inresponse to detecting an air pressure that exceeds the compensationthreshold. In other implementations, the imaging system 100 may beconfigured to automatically initiate the error condition check routine(for example, one or more of the routines illustrated in FIGS. 2Athrough 2E) in response to detection of an air pressure that exceeds thecompensation threshold.

In still other implementations, the imaging system 100 may applymultiple air pressure thresholds each triggering a different mitigatingaction. For example, the imaging system 100 may be configured to outputa notice on the graphical user interface instructing the user tovisually inspect the imaging sensor housing 109 if a first pressurethreshold is exceeded, to apply the error condition check routine ofFIGS. 2A through 2E if a second (higher) pressure threshold is exceeded,and to disable the imaging sensor 108 until it is thoroughly inspectedby technical support personnel if a third (highest) threshold isexceeded.

The systems and methods described above provide examples of methodsimplemented by the imaging system 100 for detecting error conditions andfor transitioning between states that govern the operation of an imagingsensor 108. FIG. 11 provides a specific example of a state diagramillustrating the interaction of various methods and systems describedabove for controlling and regulating the operation of the imaging sensor108. In the example of FIG. 11, the imaging sensor 108 is operated inone of three states: a low power state, a ready state, and an armedstate.

When operating in the low power state 1101, the imaging sensor 108cannot be activated—that is the imaging sensor 108 cannot capture imagedata—and the x-ray source 107 cannot be activated to emit x-rayradiation. In some implementations, some of the other sensor and/orlogic components of the imaging sensor 108 are also turned off orpowered down when the imaging sensor 108 is operating in the low-powerstate.

When operating in the ready state 1103, the image sensor array 115 isturned OFF, but can be activated (i.e., operated to capture image data)upon a transition from the ready state 1103 into the armed state 1105.In the example of FIG. 11, the imaging sensor 108 cannot transitiondirectly from the low-power state 1101 into the armed state 1105.

When operating in the armed state 1105, the image sensor array 115 isturned on and will capture image data in response to a user-activated oran automated trigger. In the example of FIG. 11, the x-ray source 107can be activated to emit x-rays when the imaging sensor 108 is operatingin the armed state 1105 and when the output of the multi-dimensionalsensor 123 indicates that the imaging sensor 108 is aligned with thex-ray source 107.

When operating in the low-power state 1101, the imaging sensor 108 cantransition into the ready state 1103 in response to detecting that theimaging sensor 108 has been removed from the “garage” 303 (for example,the method of FIG. 4) or in response to detecting an acceleration thatexceeds a threshold (for example, the method of FIG. 5). In the exampleof FIG. 11, the imaging sensor 108 cannot transition directly into thearmed state 1105 when operating in the low-power state 1101.

When operating in the ready state 1103, the imaging sensor 108 cantransition into the armed state 1105 in response to detecting a gesturepattern (for example, the method of FIG. 8). The imaging sensor 108 canalso transition from the ready state 1103 into the low-power state 1101in response to detecting placement of the imaging sensor 108 in the“garage” 303 (for example, the method of FIG. 4) or in response todetecting an acceleration equal to zero for a defined period of time(for example, the method of FIG. 5).

When operating in the armed state 1105, the imaging sensor 108 can beoperated to capture x-ray image data. The imaging sensor 108 cantransition from the armed state 1105 into the ready state 1103 inresponse to detecting that the imaging sensor 108 has been removed froma sensor positioner (for example, the method of FIG. 7). In the exampleof FIG. 11, the imaging sensor 108 can also transition directly from thearmed state 1105 into the low-power state 1101 in response to detectingthat the imaging sensor 108 has been placed in the storage “garage” 303(for example, the method of FIG. 4) or in response to detecting anacceleration equal to zero for a defined period of time (for example,the method of FIG. 5).

In some imaging systems 100 implementing the state diagram of FIG. 11,the imaging system 100 may be configured to perform one or more of theerror condition check routines described above in reference to FIGS. 2Athrough 2E and FIG. 10 when the imaging sensor 108 transitions from theready state 1103 into the armed state 1105. In some implementations, theimaging system 100 also performs one or more of these error conditioncheck routines either periodically while operating in the armed state1105 or after capturing a defined number (for example, one or more) ofx-ray images while operating in the armed state 1105.

FIG. 11 is only one example of a state diagram that may be implementedby an imaging system 100. In other implementations, the imaging system100 may implement more operating states including one or more“low-power” states, one or more “ready” states, and one or more “armed”states. In other implementations, more, fewer, or different criteria maybe used to initiate transitions from one operating state to another.

Also, the examples discussed above describe the “imaging system 100”monitoring the outputs from the sensor components of the imaging sensor108 and determining whether to initiate a state transition. Accordingly,in various different embodiments, these and other methods may beexecuted by one or more of the various processors included in theimaging system 100 or other processing systems communicative coupled tothe imaging system 100. For example, in some implementations, themethods for analyzing the sensor outputs, determining when to initiate astate transition, and performing an error condition check routine areprovided by the electronic processor 103 of the imaging systemcontroller computer 101 executing instructions stored on the memory 105.However, in other implementations, these methods are provided by thesensor electronic processor 117 executing instructions stored on thesensor memory 119. In still other implementations, some of the methodsare performed by the electronic processor 103 of the imaging systemcontroller computer 101 while other methods are performed by the sensorelectronic processor 117 or methods are performed cooperatively byinstructions executed on both the sensor electronic processor 117 andthe electronic processor 103 of the imaging system controller computer101.

Finally, although several of the methods illustrated in the attacheddrawings and discussed in the examples above are described as“sub-routines,” in other implementations, one or more of these methodsmay be implemented as a looped process. For example, one or more of theindividual methods illustrated in FIGS. 2B, 2C, 2D, 2E, 4, 5, and 10 canbe implemented as processes that continually repeat execution uponcompletion of each iteration or after a defined time delay. Furthermore,in some implementations, multiple individual looped processes can beimplemented to execute in parallel as separate individual loops.

Thus, the invention provides, among other things, imaging systemsconfigured to transition an imaging sensor between multiple operatingstates, including a low-power state, based on outputs from sensorcomponents integrated into an imaging sensor housing. Various featuresand advantages of the invention are set forth in the following claims.

What is claimed is:
 1. A method for determining that an intra-oralimaging sensor is positioned in a mouth of a patient, the intra-oralimaging sensor including a temperature sensor, the method comprising:receiving, by an electronic processor, an output from the temperaturesensor indicative of a sensed temperature; and determining that theintra-oral imaging sensor is positioned in the mouth of the patientbased at least in part on the output from the temperature sensor.
 2. Themethod of claim 1, further comprising comparing, by the electronicprocessor, the sensed temperature to a temperature threshold, andwherein determining that the intra-oral imaging sensor is positioned inthe mouth of the patient includes determining that the intra-oralimaging sensor is positioned in the mouth of the patient based at leastin part on the comparison of the sensed temperature to the temperaturethreshold.
 3. The method of claim 1, further comprising: determining, bythe electronic processor, a rate of change of the sensed temperature;and comparing the rate of change of the sensed temperature to arate-of-change threshold, wherein determining that the intra-oralimaging sensor is positioned in the mouth includes determining that theintra-oral imaging sensor has been moved from outside of the mouth toinside of the mouth when the rate of change of the sensed temperatureexceeds the rate-of-change threshold.
 4. The method of claim 3, furthercomprising: monitoring, by the electronic processor, the output of thetemperature sensor over a period of time; and determining a plurality ofsensed temperatures in a sequence of sensed temperatures based at leastin part on the monitored output of the temperature sensor over theperiod of time, wherein determining the rate of change of the sensedtemperature includes determining a first derivative of the sequence ofsensed temperatures, and wherein comparing the rate of change of thesensed temperature to the rate-of-change threshold includes comparingthe first derivative of the sequence of sensed temperatures to therate-of-change threshold.
 5. The method of claim 4, further comprisingcomparing the sensed temperature to a temperature threshold, and whereindetermining that the intra-oral imaging sensor is positioned in themouth of the patient includes determining that the intra-oral imagingsensor has been moved from outside of the mouth to inside of the mouthwhen both the sensed temperature exceeds the temperature threshold andthe first derivative of the sequence of sensed temperatures exceeds therate-of-change threshold.
 6. The method of claim 1, further comprising:monitoring, by the electronic processor, the output of the temperaturesensor over a period of time; determining a plurality of sensedtemperatures in a sequence of sensed temperatures based at least in parton the monitored output of the temperature sensor over the period oftime; determining a second derivative of the sequence of sensedtemperatures; and comparing, by the electronic processor, the secondderivative of the sequence of sensed temperatures to a temperatureacceleration threshold, wherein determining that the intra-oral imagingsensor is positioned in the mouth of the patient includes determiningthat the intra-oral imaging sensor has been moved from outside of themouth to inside of the mouth when the second derivative of the sequenceof sensed temperatures exceeds the temperature acceleration threshold.7. The method of claim 1, further comprising: monitoring, by theelectronic processor, the output of the temperature sensor over a periodof time; determining a plurality of sensed temperatures in a sequence ofsensed temperatures based at least in part on the monitored output ofthe temperature sensor over the period of time; determining a currenttemperature based on a most recent output of the temperature sensor;determining a first derivative of the sequence of sensed temperatures,the first derivative being indicative of a rate of change of the sensedtemperature over the period of time; determining a second derivative ofthe sequence of sensed temperature, the second derivative beingindicative of a rate at which the rate of change of the sensedtemperature is changing over the period of time; comparing, by theelectronic processor, the current temperature to a temperaturethreshold; comparing, by the electronic processor, the first derivativeof the sequence of sensed temperatures to a rate-of-change threshold;and comparing, by the electronic processor, the second derivative of thesequence of sensed temperatures to a temperature acceleration threshold,wherein determining that the intra-oral imaging sensor is positioned inthe mouth of the patient includes determining that the intra-oralimaging sensor has been moved from outside of the mouth to inside of themouth in response to determining that at least three defined conditionsare simultaneously satisfied, wherein the three defined conditionsinclude the current temperature exceeds the temperature threshold, thefirst derivative of the sequence of sensed temperatures exceeds therate-of-change threshold, and the second derivative of the sequence ofsensed temperatures exceeds the temperature acceleration threshold. 8.The method of claim 1, further comprising: transitioning the intra-oralimaging sensor from a first operating state into a second operatingstate in response to determining that the intra-oral imaging sensor ispositioned in the mouth of the patient; and operating the intra-oralimaging sensor in the second operating state until a separate statetransition criteria is satisfied.
 9. The method of claim 8, furthercomprising: receiving a manual override signal from a user interface;and transitioning the intra-oral imaging sensor from the first operatingstate into the second operating state in response to receiving themanual override signal regardless of the output of the temperaturesensor.
 10. The method of claim 1, further comprising: selectivelyoperating the imaging system in each of a plurality of differentoperating states; automatically altering, by the electronic processor,the operating state of the imaging system in response to determiningthat the intra-oral imaging sensor is positioned in the mouth of thepatient; and automatically altering, by the electronic processor, theoperating state of the imaging system based at least in part on anoutput from a multi-dimensional sensor, wherein the multi-dimensionalsensor is at least partially housed within a housing of the intra-oralimaging sensor and includes a three-dimensional accelerometer, athree-dimensional gyroscope, and a three-dimensional magnetometer. 11.The imaging system of claim 1, wherein the electronic processor isfurther configured to monitor the output of the temperature sensor overa period of time, determine a plurality of sensed temperatures in asequence of sensed temperatures based at least in part on the monitoredoutput of the temperature sensor over the period of time, determine acurrent temperature based on a most recent output of the temperaturesensor, determine a first derivative of the sequence of sensedtemperatures, the first derivative being indicative of a rate of changeof the sensed temperature over the period of time, determine a secondderivative of the sequence of sensed temperatures, the second derivativebeing indicative of a rate at which the rate of change of the sensedtemperature is changing over the period of time, compare the currenttemperature to a temperature threshold, compare the first derivative ofthe sequence of sensed temperatures to a rate-of-change threshold, andcompare the second derivative of the sequence of sensed temperatures toa temperature acceleration threshold, wherein the electronic processoris configured to determine that the intra-oral imaging sensor ispositioned in the mouth of the patient by determining that theintra-oral imaging sensor has been moved from outside of the mouth toinside of the mouth in response to determining that at least threedefined conditions are simultaneously satisfied, wherein the at leastthree defined conditions include the current temperature exceeds thetemperature threshold, the first derivative of the sequence of sensedtemperatures exceeds the rate-of-change threshold, and the secondderivative of the sequence of sensed temperatures exceeds thetemperature acceleration threshold.
 12. An imaging system comprising: anintra-oral imaging sensor including an image sensing component and atemperature sensor; and an electronic processor configured to receive anoutput from the temperature sensor indicative of a sensed temperature,and determine that the intra-oral imaging sensor is positioned in themouth of the patient based at least in part on the output of thetemperature sensor.
 13. The imaging system of claim 12, wherein theelectronic processor is further configured to compare the sensedtemperature to a temperature threshold, and wherein the electronicprocessor is configured to determine that the intra-oral imaging sensoris positioned in the mouth of the patient by determining that theintra-oral imaging sensor is positioned in the mouth of the patientbased at least in part on a comparison of the sensed temperature to thetemperature threshold.
 14. The imaging system of claim 12, wherein theelectronic processor is further configured to determine a rate of changeof the sensed temperature, and compare the rate of change of the sensedtemperature to a rate-of-change threshold, wherein the electronicprocessor is configured to determine that the intra-oral imaging sensoris positioned in the mouth of the patient by determining that theintra-oral imaging sensor has been moved from outside the mouth toinside of the mouth when the rate of change of the sensed temperatureexceeds the rate-of-change threshold.
 15. The imaging system of claim14, wherein the electronic processor is further configured to monitorthe output of the temperature sensor over a period of time, anddetermining a plurality of sensed temperatures in a sequence of sensedtemperatures based at least in part on the monitored output of thetemperature sensor over the period of time, wherein the electronicprocessor is configured to determine the rate of change of the sensedtemperature by determining a first derivative of the sequence of sensedtemperatures, and wherein the electronic processor is configured tocompare the rate of change of the sensed temperature to therate-of-change threshold by comparing the first derivative of thesequence of sensed temperatures to the rate-of-change threshold.
 16. Theimaging system of claim 15, wherein the electronic processor is furtherconfigured to compare the sensed temperature to a temperature threshold,and wherein the electronic processor is configured to determine that theintra-oral imaging sensor is positioned in the mouth of the patient bydetermining that the intra-oral sensor has been moved from outside ofthe mouth to inside of the mouth when both the sensed temperatureexceeds the temperature threshold and the first derivative of thesequence of sensed temperatures exceeds the rate-of-change threshold.17. The imaging system of claim 12, wherein the electronic processor isfurther configured to monitor the output of the temperature sensor overa period of time, determine a plurality of sensed temperatures in asequence of sensed temperatures based at least in part on the monitoredoutput of the temperature sensor over the period of time, determine asecond derivative of the sequence of sensed temperatures, and comparethe second derivative of the sequence of sensed temperatures to atemperature acceleration threshold, wherein the electronic processor isconfigured to determine that the intra-oral imaging sensor is positionedin the mouth of the patient by determining that the intra-oral imagingsensor has been moved from outside of the mouth to inside of the mouthwhen the second derivative of the sequence of sensed temperaturesexceeds the temperature acceleration threshold.
 18. The imaging systemof claim 12, wherein the electronic processor is further configured totransition the intra-oral imaging sensor from a first operating stateinto a second operating state in response to determining that theintra-oral imaging sensor is positioned in the mouth of the patient; andoperate the intra-oral imaging sensor in the second operating stateuntil a separate state transition criteria is satisfied.
 19. The methodof claim 18, further comprising a user interface configured to generatea manual override signal in response to a user input, wherein theelectronic processor is further configured to receive the manualoverride signal from the user interface, and transition the intra-oralimaging sensor from the first operating state into the second operatingstate in response to receiving the manual override signal regardless ofthe output of the temperature sensor.
 20. The imaging system of claim12, wherein the intra-oral imaging sensor further includes a housing anda multi-dimensional sensor at least partially housed within the housing,the multi-dimensional sensor including a three-dimensionalaccelerometer, a three-dimensional gyroscope, and a three-dimensionalmagnetometer, wherein the electronic processor is further configured toselectively operate the imaging system in each of a plurality ofdifferent operating states, alter the operating state of the imagingsystem in response to determining that the intra-oral imaging sensor ispositioned in the mouth of the patient, and alter the operating state ofthe imaging system based at least in part on an output from themulti-dimensional sensor.